Improvement in vault-covers



UNITED STATES PATENT FFICE.

IMPROVEMENT IN VAULT-COVERS.

Specification forming part of Letters Patent No. 156,411, dated November 3, 1874; application filed December 30, 1873.

To all whom it may concern:

Be it known that I, WILLIAM DALE, of the city of Washington, in the District of Columbia, have invented an Improvement in Vault- Govers, of which the following is a specification:

Figure 1 is a perspective view of my improved cover, showinga dish, having across the inner surface of its bottom plate ribs, to act in retaining the materialwith which it is filled, and an inwardly-prey ectin g ledge or pins upon the inner surface of its vertical portion for the same purpose, while the bottom plate is perforated for the purpose of allowing water to escape, and air to enter to facilitate the hardening of the cement. Fig. 2 is a transverse section. showing the position of the parts above alluded to.

I now use in most instances cement to fill the cavity of the dish,.and up to the date of my invention no means had been provided forthe escape of the moisture from that portion thereof which is in the lower portion of said dish; and, as the upper portion of the filling soon becomes hardened, the moisture remainsin the great body of thesame, and

prevents it from hardening, and, finally, deteriorates the same to such an extent that it 'does not become as hard as that upon the contact with a considerable portion of the under surface of the filling, and thus aid in hardening the same.

Ihave described my invention as applicable to vault-covers only; but it is apparent that it is equally applicable to man-traps or any other form of opening in streets or sidewalks,

I do not in this case lay any'claim to the dovetailed ribs B, or inwardly-projecting ledge or pins 0 or O, as they are covered by a claim in another case previously presented by me.

I claim- A dish, for the reception of cement or other material, for forming a vault-cover, having in its lower surface a series of openings for the escape of moisture and the admission of air, substantially as and for the purpose set forth.

In testimony whereof I have signed myv name to this specification in the'presence of two subscribing witnesses.-

WILLIAM DALE. Witnesses:

D. P. HOLLOWAY, A. RUPPERT. 

